The 164V LF amplifier triode from Mullard dates from 1929 and was introduced at the Olympia show.

The flattened cathode is indirectly heated. The anode box lies horizontally within the envelope. The stamped pattern gives rigidity to the thin bright metal used for the anode. The grid extends beyond the anode box and is shaped so that it is --[ ]-- in section. This allows the outer part of the grid wires to radiate heat and so prevent secondary emission.

The balloon envelope is 50 mm in diameter and, excluding the B5 base pins, is 91 mm tall.

References: 1931 datasheet & ¹⁰⁴⁰. Type 164V was first introduced^¶ in 1929.

 
Pin Connections

B5	1	2	3	4	5
	a	g1	h	h	k

 
Absolute Maximum Operating Conditions^¶

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	4.0	1.0	200	-9.0	12.0	4,700	3.4

Thanks to Andy Cowley for supplying the above PDF datasheet